Camera Pinch Closeup iPhone Photo Resolution Focus Tutorial

Camera Pinch Closeup iPhone Photo Resolution Focus Tutorial

Camera Pinch Closeup iPhone Photo Resolution Focus Tutorial

If you come from a photography and camera usage going back to the (pre-digital) SLR cameras of the latter 1900 years (and even the ones that tended towards you “not adjusting much and being digital” SLR cameras) yesterday’s Camera Pinch Closeup iPhone Photo Resolution Primer Tutorial might make you think …

  • the pinch gesture is like “zoom” (with a (SLR (Single-lens Reflex) or other camera type) zoom lens or a change of focal length (telephoto) lens)

    … then …

    if you’re trying to make out an iPhone replaces a quality SLR Camera for quality of photography, we’ll take you on 3:15, over in the park … if I’m not there, start without me

  • we’d say …
    1. Correct
    2. We have no intention of saying that, but to get a better comparison feel, let’s talk about iPhone Camera “focus”

… and we want to ask, in all innocence …

Does the iPhone Camera app do “depth of field”?

… that “depth of field” (amount forward of camera that is in focus in the resultant photograph) being a concept with SLR Cameras whereby the four major controls the user has (on top of the existent (camera) lens and lens filter arrangements) regarding how a photograph’s focus and lighting will result (from the phase before any digital or photographic darkroom techniques can come into play) …

  1. speed (ie. sensitivity to light exposure) of film (if not a digital SLR Camera) … set the once after loading film
  2. lens aperture … can be manually controlled (as set by the user for those more modern digital SLR Cameras)
  3. shutter speed … can be manually controlled (as set by the user for those more modern digital SLR Cameras)
  4. focus ring controlling focal length

… the smaller that “lens aperture” (where F-stop value denominator is bigger … ie. “f/1.8″ F-stop has bigger “lens aperture” than “f/4.0″ F-stop) the more “depths” within your photograph forward of the SLR Camera will be in focus (and the camera more than likely had lines to tell you this “depth of field” range in some unit of measure such as feet or metres). Take a picture of subject matter just off into the distance and this “depth of field” might have little to no meaning, in which case you could just pick a “lens aperture” that makes the inbuilt light meter reading’s marker sit in a “sweet spot” notch with a “shutter speed” on or faster than 1/60th of a second (for most people steadying themselves just taking a non-panned subject matter). But add a totally different photograph subject matter close by with that far off view and “depth of field” thoughts can come into play. If you want a focussed close up subject with a blurred view background …

  1. focus on that foreground subject (SLR Cameras are like iPhone and iPad Camera apps whereby the rectangle in the middle of the screen should be placed over that subject of interest … SLR Cameras can then reposition with that same focal length)
  2. set one of those wider (smaller value) “lens aperture” F-stop value (and in the view finder of SLR Camera you see what becomes or loses focus as a result)
  3. set “shutter speed” to get light meter reading’s marker sit in a “sweet spot” notch

… and if that “shutter speed” is slower than 1/60th second, think of using a tripod or sitting the SLR Camera on a solid place.

Now, our experiment with the iPhone Camera app today was to see whether either (underlying) “lens aperture” and/or “shutter speed” for the iPhone Camera app changes as you, the iPhone photographer take “pinch gesture” (or not) photographs of a similar scene. On that iPhone you can control focus as per step 1 above …

… (and as we follow Nala’s nose (and eyelashes) above with an iPad Camera app) but have no manual control over the other two. So what happens?

Well, as you can see with today’s animated GIF presentation, made in that similar way to yesterday’s one

  • speed of film is always “ISO speed” 20
  • “lens aperture” F-stop value is always “f/1.8″
  • “shutter speed” is shown as “Exposure time” and this value changes between photographs (probably according to the iPhone’s inbuilt light meter … mind you, you can control brightness, as Nala well knows, to the right of the “focal length” rectangle)

So no, the iPhone Camera app does not do all aspects of “depth of field” that an SLR Camera can control, but the iPhone Camera app user can set the focal length by controlling what subject matter sits at the center of the photograph being taken, just as an SLR Camera can do also to control the “focal length” (and this alone may suit the ideas of what you are trying to achieve with your photograph)


Previous relevant Camera Pinch Closeup iPhone Photo Resolution Primer Tutorial is shown below.

Camera Pinch Closeup iPhone Photo Resolution Primer Tutorial

Camera Pinch Closeup iPhone Photo Resolution Primer Tutorial

Because we couldn’t categorically say …

the resolution is the same, the photo dimensions are the same for two versions of an iPhone Camera app created photo of a scene, one not pinched and the another a closeup of detail within that scene via a user pinch gesture

… we decided to do our own test with photographs of a bee interested in Jacaranda tree petals. The test involved …

  • in iPhone Camera app take at least one non-closeup non-pinched photo of the bee (we ended up taking two such non-closeup non-pinched photos)
  • in Camera app take at least one closeup pinched photo of the bee (we ended up taking four such closeup pinched photos)
  • via Share icon share these via Email to myself, picking the “Actual Size” mode of photo storage
  • on this MacBook Pro Gmail webmail, downloaded resultant email attachment as a zip file we tap to unzip
  • opened those 6 unzipped photos in Finder “Show items as icons, in a list” display mode … for each …
  • screenshotting each via Shift-Command-Control-3 … to slides (via Paintbrush’s “New from Clipboard”/”Save As…”) …
  • we compile into today’s animated GIF presentation … from which we can conclude, at least from this test, that …
  • yes, the resolution is the same, the photo dimensions are the same for two versions of an iPhone Camera app created photo of a scene, one not pinched and the another a closeup of detail within that scene via a user pinch gesture

What else could be the case? With pinch operations perhaps resolution is lost and image sizes change, is one scenario. But no, pinch away for your detail closeup photographs with whatever level of impunity you normally adopt with an iPhone?!

If this was interesting you may be interested in this too.


If this was interesting you may be interested in this too.

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